A. Field of the Invention
The present invention relates to an ultrasound diagnosis system including an ultrasound probe, and more particularly, to an ultrasound diagnosis system including a motor driving multi-plane type ultrasound probe that can acquire image data at a plurality of scanning planes, by rotating an arranged surface of ultrasound transducers in a head portion of the probe across a prescribed range of angles.
B. Background of the Invention
An ultrasound diagnosis system transmits ultrasound from ultrasound transducers (hereinafter: “transducers) installed in a head portion of the ultrasound probe to an object, such as a patient. The transducers receive ultrasounds reflected from the object as image data that is generated in accordance with differences of acoustic impedances of an organ of the object. The received image data is processed as an image of the organ and displayed on a monitor.
Since the ultrasound diagnosis system can easily obtain and observe two dimensional images in real-time by simply touching an ultrasound probe on a patient's body, it is widely used in various diagnoses. To examine a function or the status of an organ in a patient's body, an ultrasound diagnosis system acquires vital data based on reflected ultrasounds from an organ or blood cells of the object. To perform the ultrasound diagnosis, two types of images (B mode images and color Doppler images) are used. B mode images are acquired by using a method of ultrasound reflections. Color Doppler images are acquired by using an ultrasound Doppler method.
In particular, a trans-esophageal ultrasound diagnosis is used for performing a cardiac diagnosis. To perform the trans-esophageal ultrasound diagnosis, head portion installed ultrasound transducers are inserted into the esophagus of a patient body so as to place the transducers at an appropriate position in a vicinity to a heart while avoiding the influences of ribs and a lung, since these organs are usually prevent ultrasound transmission and reception to and from the heart. By placing the transducers in the vicinity of a heart, the trans-esophageal ultrasound diagnosis can obtain and observe a high resolution image data of the heart or a vicinity blood tube system.
Typically, the trans-esophageal ultrasound diagnosis uses an ultrasound probe including a head portion in which a plurality of transducers are arranged in a surface. In order to insert the probe into a patient body, the head portion is connected to a flexible guiding tube that is constructed similar to an endoscope. The arranged surface of the plurality of transducers is rotated on a vertical axis to the surface in order to acquire image data at a desired angle. The arranged ultrasound emission surface is hereinafter referred to as a “scanning plane.” In the trans-esophageal ultrasound diagnosis, it is conventionally difficult to place the scanning plane at a desired direction by using an angle knob as used in an endoscope, since the surface is needed to move in a limited narrow area of an esophagus. Accordingly, it has been proposed to use a motor driving multi-plane type ultrasound probe for the trans-esophageal ultrasound diagnosis. The motor driving multi-plane type ultrasound probe can place the scanning planes at desired directions by a motor driven rotation of the transducers.
In particular, since the motor driving multi-plane type ultrasound probe has good operability, it is useful as a cardiac diagnosis to easily and accurately obtain cardiac image data by rotating the transducers installed in a head portion of an ultrasound probe. Conventionally, two types of the motor driving multi-plane type ultrasound probe have been proposed. One is a successive rotation type probe in which the transducers are successively rotated in a prescribed direction. The other is a reverse rotation type probe in which an arranged surface of the transducers is rotated in one direction in a prescribed angle range from a zero degree angle to a target angle of less than 180 degrees. In the reverse rotation type probe, when the transducers are rotated up to the target angle, an operator moves the transducers in an opposite (reversing) direction as suggested in Japanese Patent Application Publication 2006-312103.
In the successive rotation type motor drive multi-plane ultrasound probe, the transducers in the head portion of the probe transmit signals through a slip ring provided between a rotation portion of the head and a fixed portion of the head. The successive rotation type probe has various problems and defects. Due to the size of the slip ring installed in the head portion, an external size of the head portion of the successive rotation type motor drive multi-plane ultrasound probe becomes a larger size. Consequently, it becomes difficult to insert the head portion into an esophagus of a patient without causing the patient to experience pain. Further, the slipping noises generated from the slip ring cause deteriorations in the quality of the generated image data to occur.
In the reverse rotation type motor drive multi-plane ultrasound probe, a plurality of the transducers installed in a head portion of the probe is connected to each of the signal lines printed on a flexible printed circuit board (FPC) with a narrow pitch between each of the signal lines. Consequently, it becomes possible to make the head portion of the probe in a smaller size than the head for the successive rotation type probe. Since the FPC connection in the head of the reverse rotation type ultrasound probe does not generate such slipping noises as in the successive rotation type ultrasound probe, it becomes possible to acquire better quality image data.
Usually, the reverse rotation type motor driving multi-plane ultrasound probe includes two instruction buttons for respectively instructing rotation in a first direction, for instance, a clockwise (CW) direction and a second direction opposite to the first direction, i.e., a counterclockwise (CCW) direction. The transducers installed in a head portion are rotated in a desired direction by selecting the direction instruction buttons provided in an angle portion of the probe. For instance, suppose that a CCW rotation direction is selected by using a CCW button, image data is collected at a plurality of scanning planes by successively rotating the transducers in a CCW direction in a predetermined angle range within 180 degrees.
In conventional techniques, when the transducers approach a target angle of, for instance, almost 180 degrees by rotating in an instructed CCW direction, there exists a need for an operator to select a reverse CW direction by using the CW instruction button in order to reverse the transducers 180 degrees so as to place the scanning plane at an adjoin angle position to the target angle in the CCW direction. Thus, when the transducers approach the vicinity of the target angle, there exists a need for an operator to change the rotation speed of the transducers from a normal speed to a lower speed in order to achieve an accurate head angle position. These operations are complicated and burdensome for an operator. Thus, it takes a lot of time for setting the transducers in a desired angle position. Since it largely reduces efficiencies of observations through ultrasound images, the conventional reverse rotation type motor driving multi-plane ultrasound probe also has serious problems.